Improvement in railroad-car springs



W. SLIGER, decd. C. H. SLI CER, Admr.

I Railroad Car Springs. 1

NO.'140,084. A Patentedlunel7,1873- v AM PHoTm/moeRAPmc ca. N)f(L7sBOR/VEPROCESS.) V

UNITED STATES PATENT OFFICE.

CHARLES H. SLICER, OF BALTIMORE, MARYLAND, ADMINISTRATOR OF WILLIAM SLIGER, DECEASED.

IMPROVEMENT IN RAILROAD-CAR SPRINGS.

Specification forming part of Letters Patent No.

140,084, dated J ure 17, 1873; application filed January 4, 1871.

'showin g more clearly the double-face taper of the blade of which the spring is made, the said double taper commencing from the point A. Fig. 3 represents a side of the same. Fig. 4, a vertical section thereof; Fig. 5 represents a side view of the peculiar shaped blade or blank from which the spring is made, showing its double-edge taper to form the fixed base and the elevated spring portion thereof; and Fig. 6, an edge of said blank,

showing the double-face taper.

The invention herein claimed relates to that class of springs known as conical volute springs for locomotives, railroad carriages, and other vehicles.

Efforts have been made to produce apractically successful spring of this character 5 and among them a conical volute spring has been made from a strip of steel, rectangular in every part ofits section, and coiled or bent around a helical or conical spiral form, and so that the lower part of each coil shall extend within the upper part of the coil below it,

making, in effect, a plate parallel both in width and thickness, into a coiled spring, such as made by Underhill in 1848, and Baker in 1838.

Such springs have also been made from a flat steel blade with parallel edges, but tapering in thickness from one end to the other on both sides alike, and wound spirally into a cone, with its thick end forming the point of the base.

In another case, the blank or plate for the conical spring has been made tapered for the last three coils,-on both sides, to the end which forms the bearing point.

In each of these cases the plate has been wound into a volute, and subsequently formed into a cone, or wound spirally into a cone, so as to sustain pressure and deflection in the direction of the breadth of the metal; but in either case of forming the cone, the plate is subjected to an oblique torsion in the direction of its width, which necessarily weakens the spring and diminishes its resisting power.

Moreover, the spring itself can only be formed by these methods, by forcing the blade, under heavy strain, edgewise from the base, so that the tendency of such spring-coil is to seek the point from which it was drawn.

The invention herein claimed not only differs from the foregoing methods of forming this kind of spring in material and highly advantageous features of construction of the blade, but also in the functions and results of the" spring, due alone to these new features.

These improvements consist, first, of a plate or blank for the spring, the lower edge whereof has double opposite tapers for separate and distinct purposes, viz., the first or short taper starting from the actual base-point of the spring, to form a neutral coil or seat for the spring, and not intended to have any spring function whatever, but to act as a permanent base or support from which the spring portion of the blade starts, the base-point mentioned being the fulcrum-point of the spring-blade while the longer portion tapers from said basepoint, in a direction opposite to that of the neutral base to form the spring, the object and aim of these combined long and short edge tapers being, first, to obtain the proper elevation to form the conical spring without straining or stretching the lower edge of the plate, or contracting its upper edge under the operation of coiling; and, second, to so reduce the quantity of the metal as the coil approaches the apex as to cause the smaller or upper coils to yield gradually in proportion to the amount of metal in them, and consequently to allow them to recede to bring into action the succeeding coils, as by this construction each succeeding coil, from the apex to the fulcrum-pointat the neutral base,has a gradual increased quantity of metal in its width, and consequently each coil in its turn downward is capable of supporting an increase of weight over and above that of the preceding upper coils, it being distinctlynnderstood that the greatest width of the blade is directly at the fulcrum-point, and from which point it diminishes to its opposite points or ends to about one-half the said point of greatest width. The second feature of this invention consists in tapering the blade face-wise, upon what forms the outer side of the spring when coiled, both ways from its fulcrum-point, which is not only the point of greatest width, but the point of greatest thickness of the blade. This double taper is gradual and terminates in thin cdgesat the ends, the object and advantage of which is to overcome the straining or fracturing of the face of the blade in forming the coil by reason of shortening the inner face of the blade and increasing the length of its outer face. Such increased length, being necessary, is obtained by this gradual diminishing taper of the face of the blade, as stated; a further advantageous result from such facetaper of the spring portion of the blade being the same as that growing out of the edge taper-that is to say, that each succeeding coil from the apex to the base, having an increased quantity of metal in thickness, will, in its turn, sustain an increased amount of weight when in action, but this action only refers to the spring portion of the blade starting from its fulcrum-point; the marked and distinguishing feature of the invention being the production of a spring more even and uniform in its action, and having a greater carryin g capacity than any other volute spring here tofore made from an equal weight of metal, while its yielding action is at all times commensurate with the work it has to perform, and will effect a great saving in metal.

In the drawings, Figs. 5 and 6 represent this new form of spring-blade, A being the fulcrum-point, A B the neutral coil or inactive part, and O the elevation which forms the lever-spring when the plate is coiled; while in Fig. 6 A D represent the short-face taper of the neutral coil, A E, the long-face taper of the elevated spring portion. The plate is of a single piece of steel or other metal, and, when formed into a spring, is a pyramid based upon a cylinder, which latter is about onethird the height of the whole spring and forms the base or neutral coil A B. This latter coil is tapered to one'half its width, and to an edge in thickness. The bottom edge of this neutral coil rests upon and within a metal cup, the rim of which prevents the spring from spreading and keeps it firmly in place. The pyramidal part of the spring is formed from the elevation A 0, starting from the fulcrum-point A, and is divided into lessening spiral divisions until the last or top coils end in a plane.

- The plates of which the springs are formed should be well hammered throughout their whole length, and always regularly tapered from base to point, as upon this depends much the efficiency of the spring.

The proportionate length of the plate and of consequence the taper will depend on the size and strength of the spring required, but to taper it from its largest part at the base each way to half its width is a good general rule.

The spring, when'formed for light purposes and easy motion, will be generally of about the following proportions, viz The height of the spring to be not more than the diameter of its base; each successive coil to show about half the plate when slightly pressed; the opening in the top of the spring to be about one-sixth the greatest diameter of the spring; the greatest width of the plate to be one-third that diameter; and its width at the point to be half of that last mentioned; its thickness to be one-fifth its greatest width; its whole length to be about thirtysix times its greatest width. Three-fourths of its whole length forms the spring A U, and the remaining fourthforms its base A B, or neutral coil, which remains stationary. When great loads are to be carried it is better, perhaps, to multiply the number of springs than to increase their weight. The springs made in this way, properly proportioned and arranged for use, will bear to be driven entirely home upon their seats without injury, and even beyond this, if arranged for the purpose. Aspring three inches in height, made of a plate one inch at its widest part and half-inch at its point, would have a movement or vibration of two and a halt inches. A spring weighing two ounces, the plate of which in its whole length is eighteen inches, spring length fourteen inches, width half-inch, tapered to a quarter of an inch, onetenth of an inch thick, also tapered, requires one hundred and fifty pounds to bring it down upon its seat, and will ride one-half that weight.

The spire or elevated part A G of the spring, tapered regularly its whole length, allows it to vibrate regularly through its whole length without throwing extra strain on any one of the coils.

The coils of the spring, made by the abovenamed proportions, should be in number about eight, beginning and ending with their points or ends on the same side of the spriu g. Six of these coils are active or springcoils; the remaining two, forming the base and top, are not intended to spring. The plate should be hammeredalittle, rounding on its outer face in the cross-section. The spring possesses great elasticity, due to its long, light, and tapered plate, while its great strength and endurance are due to the fact that while it retains a great spring leverage from a fulcrum-point it concentrates the leverage around the point of pressure, thereby reducing its effective length as a lever to one-eighteenth part of its natural leverage when straight, or,' in other words, bringing its fulcrum-point to within half an inch to three inches (according to the size of the spring) of the point at which the weight is taken. Moreover, the motion of the natural leverage of the spring gives it a tortuous movement, following the direction of the top of the plate, so that it is impossible to injure it by rupture or cast, for the spring possesses the quality of quietly taking its place upon its seat when hard pressed, and is always ready to start up again with great strength and power at the removal of the pressure. This it is impossible for a coil-spring to accomplish, whose coils are formed or drawn from a plate in the direction of its width.

Having described the invention of the said WILLIAM SLIGER, what is claimed under this Patent is 

